1. Field of the Invention
The present invention relates to a body structure for a vehicle and more particularly to a connecting structure of an upper part of a center pillar of the vehicle.
2. Discussion of Related Arts
With respect to a body structure for connecting a center pillar with a side rail of a vehicle, Japanese Patent Application No. Toku-Kai-Hei 11-348821 proposes a connecting structure constituted by a panel side outer integrally formed with a center pillar outer and a side rail outer, a side rail inner, a center pillar inner and a reinforcement.
Further, with respect to another connecting structure of a center pillar with a side rail, there is a connecting structure shown in a perspective view of FIG. 7 showing an upper connecting portion of a center pillar and in a sectional view of FIG. 8 taken along a line VIIIxe2x80x94VIII of FIG. 7. This connecting structure of the center pillar comprises a side rail, a center pillar and a reinforcement disposed in the center pillar. That is, a side rail 50 provided outside of a vehicle body has a closed cross section formed by a side rail outer 52 extending in a longitudinal direction of a vehicle and a side rail inner 54 disposed inside of the side rail outer 52 and extending in a longitudinal direction of the vehicle.
The center pillar 56 is constituted by a center pillar outer member 62 and a center pillar inner member 64. The center pillar outer member 62 is bent outwardly at the upper portion thereof along the outer shape of the side rail outer member 52 and is superposed on the outer surface of the side rail outer member 52. Reference numeral 66 of FIG. 8 denotes a drip rail and reference numeral 68 denotes a roof panel.
Further, FIG. 9 shows still another example of the upper connecting structure of a center pillar. There are differences between the upper connecting structure of the center pillar shown in FIG. 7 (or FIG. 8) and that shown in FIG. 9 in providing a center pillar outer reinforcement 70 inside of the center pillar outer 62 and providing a welding surface 72 (shown in a two-dots chain line of FIG. 7) in the side rail outer 52. That is, the top portion of the center pillar outer reinforcement 70 is interposed into the side rail constituted by the side rail outer 52 and the side rail inner 54 and is welded at the upper portion thereof to the back surface of the side rail outer 52.
However, the aforesaid upper connecting structure of the center pillar has a problem that the connecting portion of the center pillar with the side rail is easy to be broken when a big load is exerted from the lateral side of a vehicle in case of a side-on collision and the like. Accordingly, in order to increase the strength of the connecting portion of the center pillar with the side rail, there are countermeasures such as using plate material with large thickness for the constituents of the side rail, center pillar and the like, adding reinforcements thereto et cetera.
However, using steel plates with large thickness for the center pillar, side rail and the like causes bad weldability, weight increase and cost increase. Further, additional reinforcements require an establishment of new welding surfaces and the welding surfaces themselves have a possibility of providing starting points of breakage, depending upon the position and configuration of the reinforcements. Further, in case where high tension steel plates are used for material of the side rail and the like, it is necessary to fix bent edges of the high tension steel plates by beads in order to prevent spring back phenomena after molding. In this case, sometimes the beads themselves become starting points from which breakage of the side rail start.
It is an object of the present invention to provide an upper connecting structure of a center pillar having a large rigidity and capable of efficiently dispersing a load exerted on the center pillar from the lateral side of a vehicle to a side rail.
In order to attain the object, an upper connecting structure of a center pillar of a vehicle for connecting said center pillar with a side rail comprises a ridge line formed on the side rail outer and extending in a longitudinal direction of the vehicle and a plurality of bead sections formed on the side rail outer and provided across the ridge line in the vicinity of a connecting portion of the side rail outer with the center pillar. The bead sections are formed with the connecting portion of the side rail outer and the center pillar between.